兩階段成長對微波電漿輔助化學氣相沉積所合成多晶鑽石性質之影響

Effects of two-stage Growth on the Polycrystalline Diamond Synthesized by Microwave Plasma Enhanced Chemical Vapor Deposition

李世鴻(Shih-Fong Lee) ； 葉忠信(Chun-Shin Yeh)

《建國科大學報》 28卷3期 (2009/04) Pp. 19-31

https://doi.org/10.6995/JCTU.200904.0019

摘要

本研究以甲烷(CH4)和氫氣(H2)作為反應氣體以一微波電漿輔助化學氣相沉積(microwave plasma enhanced chemical vapor deposition, MPECVD)系統在p型(111)矽基板上沉積多晶鑽石薄膜。多晶鑽石薄膜的性質會受成長時間、成長壓力、反應氣體比例、偏壓與否及成核的機制等因素影響。在本研究中，我們將成長階段劃分為兩個階段，其中一個具有較低壓力（成長Ⅰ階段），追隨著另一個具有較高壓力（成長Ⅱ階段）。此兩階段的成長壓力將是本研究探討的重點。觀察多晶鑽石薄膜的結晶結構、表面形態及電導率，發現兩階段成長所獲得的多晶鑽石薄膜具有本徵鑽石的半絕緣性質。這是有別於典型單一沉積單階段成長製程所合成多晶鑽石薄膜的性質。這建立了額外成長Ⅰ階段對於多晶鑽石薄膜的必要性。無成長Ⅰ階段對多晶鑽石薄膜性質的影響也一併討論。

關鍵字

微波電漿輔助化學氣相沉積MPECVD ； 多晶鑽石 ； 兩階段成長

並列摘要

In this research, reaction gases methane (CH4) and hydrogen (H2) were used in a microwave plasma enhanced chemical vapor deposition (MPECVD) system to deposit polycrystalline diamond films on p-type (111) silicon substrates. The properties of the polycrystalline diamond films are determined by the deposition time, the deposition pressure, the carbon/hydrogen ratio, the bias, and the nucleation mechanism etc. In this research, the growth stage was divided into two sub-stages including one at lower pressure (called Growth Ⅰ stage) followed by another at higher pressure (called Growth Ⅱ stage). The growth pressure of two stages will be the key point discussion in this research. Observed from the crystallographic structure, surface morphology and conductivity of polycrystalline diamond, it is found that the conductivity of polycrystalline diamond prepared with two-stage growth exhibits the semi-insulating property of diamond. This is different from that of polycrystalline diamond obtained with conventional single-stage growth. This establishes the necessity of adding the Growth Ⅰ stage in the growth of polycrystalline diamond. The influence of growth without Growth I stage on the properties of the synthesized polycrystalline diamond is also discussed.

並列關鍵字

Microwave plasma enhanced chemical vapor deposition MPECVD ； polycrystalline diamond ； two-stage growth